The present invention relates to an automatic door operator for use in swing doors.
FIG. 1 shows a typical well-known automatic swing door, in which a swing door 1 which rotates about a vertical axis is automatically opened and then closed by activating an accessing body sensing device such as mat switch 3. A signal from the mat switch 3 is transmitted through a cable 5 to a door operator 7 mounted on a header or transam 9 of a jamb or door supporting frame 8. In the operator 7, according to the signal supplied, an electric motor provided therein is energized. When the motor is energized a door swinging link mechanism 11 acting as an opening and closing means, connected through power transmission means to the electric motor, is actuated to open and close the door 1. However, when the power supply is stopped in this type of automatic swing door, the door must be opened and closed by hand. For example, in the case where an automatic swing door is also used as a fire or smoke door, the door is often left open when the power supply is stopped due to fire, since those escaping a fire usually do not stop to close the door. Thus, automatic swing doors in the prior art do not adequately perform fireproof and smokeproof functions when needed.